1. Field of the Invention
The present invention relates to a lubricating device for an engine provided with a turbocharger particularly capable of preventing mixing of air bubbles into oil that lubricates a bearing portion of the turbocharger and returns to an oil pan.
2. Description of the Related Art
In an engine provided with a turbocharger, a lubricating device supplies oil to a bearing portion of the turbocharger driven by an exhaust gas and oil lubricates in a bearing portion. In the lubricating device for an engine provided with a turbocharger, an oil is supplied by a supply pipe to the bearing portion to lubricate the bearing portion and then returns to the engine through an oil drain pipe.
In a conventional lubricating device for an engine provided with a turbocharger, as described in Japanese Patent Laid-Open Publication No. 2005-264917 (Patent Document 1) and Japanese Utility Model Laid-Open Publication No. 5-66229 (Patent Document 2), a bearing portion and a crankcase arranged to a lower portion of a cylinder block are connected by means of oil drain pipe to provide communication between an oil drain passage in the oil drain pipe and a crank chamber in the crankcase. The lubricating device passes oil discharged from the bearing portion of the turbocharger through an oil discharge port of the oil drain passage into the crank chamber and returns the oil to an oil pan disposed to a lower portion of the engine.
However, in the conventional lubricating device for an engine provided with a turbocharger, when the oil is returned into the oil pan and the crankcase, the oil may come into contact with a web of a crankshaft rotated in the crank chamber in the crankcase, which may result in spattering of oil. Thus, in the conventional lubricating device, there is a case such that air bubbles may be mixed into the oil that has dropped into the oil pan.